I think the dev is dumping some of the 117m (70% of supply) coins he has. If he is staking them, at the 50% stake per ann, then he prob only dumped his free coins and still had 117mil left to dump. The price will never rise with that premine hanging over the sell button.
If the dev had any brains he would have dragged this coin along for a month or so, propped the price up as he sold his coins. Price was over 400 a couple of days ago. All he had to do was come on here, make the right noises about upgrades etc, and he could have spun it out for a month or two.
He could still come back, claim the dump was not him but one of the people he sent free coins to, which is why he has not sent the rest. Then promise the world and dump into all the believers again.
Dam.. I have been in Crypto too long. Don't think i have a bone left in my body that's not skeptical of every coin dev.